The goal of this technology development program is to create a resource for fabrication and development of multichannel voltage and chemical sensor systems for the Neurosciences. The aim is to address the need to take advantage of new microcircuit fabrication techniques that have been recently developed within the Center for High Density Electronics at the U. Arkansas under direction of Dr. S. Ang. The plan is to work on four major aims in parallel. The first aim is to fabricate a new generation of small silicon-based multisite microprobes with sites specialized for either or both voltage or electrochemical sensing. Evaluation and study of sensor site properties will be conducted by Drs. I Fritsch (U. Ark.), D. Woodward (Wake Forest U.), and R.M. Wightman (U.N. Carolina). A second aim is to integrate the silicon probe into flexible polyimide cable system. New technologies for fabrication and coating of such materials will be adapted for in vivo Neuroscience applications. A third aim is to design and fabricate multichannel VLSI microchip headstage devices to amplify and transmit information from the voltage and electrochemcal sensor sites. The chip design will include the capacity to microstimulate through the voltage sensor sites or to apply polarization voltages at the electrochemical sites. Prototype designs already in progress will be developed further. The VLSI microcircuit will be integrated into the probe design to achieve higher desensity integration. A multiple probe configuration will be developed as the basic module is perfected. A wireless transmission system with an integrated DSP will be developed to digitize and transmit multichannel information at high rates to a host computer. A dual processor host PC workstation with the Windows NT Operating System will be further developed with software enhancements to manage the multichannel data flow and analysis. Education of students and training of users will be continued and expanded. As has been done previously, interactions with small businesses will be developed to disseminate utility of the technology development. This project will provide technology critical for ongoing research and therapeutic needs in Neuroscience of many NIH Institutes, including NIDA, NIA, NIAAA, NINDS, and NIMH.